Air circulation system for a refrigerator display case

ABSTRACT

An air circulation system for a refrigerator display case of the type including an end mounted cooling coil and blower chamber vertically spaced food supporting racks, and sliding doors giving access to the supporting trays, the invention comprising a cold air duct positioned along the bottom cabinet and directing air from the cooling chamber beneath the food supporting racks, said duct including a plurality of holes in its top surface through which the cool air passes upwardly into the cabinet. Adjustable barrier means positioned within said cold air duct to selectively close the holes therein to control the volume and location of cool air flowing into said cabinet. A warm air duct positioned along the top of said cabinet to return warmed air to said cooling coil and blower chamber and including a damper positioned between the duct and the chamber and mechanically linked to the doors of the cabinet such that the damper closes in response to the opening of the cabinet doors.

m States Ptent [191 Whitney Nov. 19, 11974 1 1 AIR CIRCULATION SYSTEM FOR A REFRIGERATOR DISPLAY CASE Robert W. Whitney, 1235 Second Ave. North, Seattle, Wash. 98109 [22] Filed: Aug. 31, 1973 [2]] Appl. No.: 393,414

[76] Inventor:

Primary Examiner-William J. Wye Attorney, Agent, or Firm-Graybeal, Barnard, Uhlir & Hughes 5 7 ABSTRACT An air circulation system for a refrigerator display case of the type including an end mounted cooling coil and blower chamber vertically spaced food supporting racks, and sliding doors giving access to the supporting trays, the invention comprising a cold air duct positioned along the bottom cabinet and directing air from the cooling chamber beneath the food supporting racks, said duct including a plurality of holes in its top surface through which the cool air passes upwardly into the cabinet. Adjustable barrier means po' sitioned within said cold air duct to selectively close the holes therein to control the volume and location of cool air flowing into said cabinet. A-warm air duct positioned along the top of said cabinet to return warmed air to said cooling coil and blower chamber and including a damper positioned between the duct and the chamber and mechanically linked to the doors of the cabinet such that the damper closes in response to the opening of the cabinet doors.

7 Claims, 7 Drawing Figures PATENIELWI 3.848.426

sum 20F 2 AIR CIRCULATION SYSTEM FOR A REFRIGERATOR DISPLAY CASE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates, in general, to refrigerator display cases, and in particular, to an air circulation system for a refrigerator display case.

2. Description of the Prior Art Refrigerator display case manufacturers have long struggled with the problem of obtaining proper cool air distribution within the display cabinet in order to keep foods fresh and cool while at the same time minimizing the visual impact of the cooling coils and cool air distribution system within the cabinet. In the past, refrigerator display cases have often included a cooling coil positioned along the inside top of the cabinet, with a fan or blower forcing air over the cold coils and down onto the food in the cabinet. This type cooling system blows the cool air directly on the food product positioned on display shelves within the cabinet thus tending to rap idly dry out the food. Additionally, the cooling apparatus in display cases of this type is usually highly visible thereby tending to further reduce the appetizing quality of the food.

Refrigerator display cases having cooling coils and blowers mounted on one end, are known, but serious display cabinet door fogging problems have often been encountered in cabinets of this type due to poor circulation and distribution of the cooled air throughout the display case. Additionally, display cases having end mounted coolers have often tended to draw inordinate amounts of warm outside air into the cabinet when the doors are opened, particularly in a cold air upflow air distribution system, where the cold air tends to flow out the bottom of the opened door while warm air moves in through the top of the door and is drawn into the warm air return duct of the cooler.

Typical known refrigerator display cases are disclosed in US. Pat. Nos. 3,584,467, 2,490,413, 2,826,046 and l,742,624.

BRIEF SUMMARY OF THE INVENTION The invention disclosed herein includes, in summary, a refrigerator display case having a display cabinet and an end mounted cooling coil and blower chamber including a cold air distribution duct extending along the bottom of the display cabinet and a warm air return duct mounted along the top of the cabinet. The cold air duct includes a plurality of air distribution holes spaced along its top surface, and'adjustable means selectively closing certain of the holes to vary the location of cold air flowing into the cabinet. Damper means adapted to close the warm air return duct in response to opening of the doors of the display cabinet are provided to reduce the amount of warm air drawn into the cabinet.

It is an object of this invention, therefore, to provide a refrigerator display case which is both visually attractive and thermally efficient.

Another object of this invention is to provide a refrigerator display case air circulation system including means for controlling the location and volume of cold air flowing into the display cabinet.

Still another object is to provide a telescopically adjustable channel within the cold air distribution duct to control the flow of air into the display cabinet.

One more object of the instant invention is to provide a refrigerator display case air circulation system including means blocking the return flow of warm air to the cooling coil when the display cabinet doors are open.

Another object is to provide a damper in the warm air return duct actuated by movement of the display cabinet doors.

Other and additional advantages will be apparent from the following discussion taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical refrigerator display case made according to the instant invention.

FIG. 2 is a section view taken along line 22 of FIG. 1.

FIG. 3 is a partial sectional view of the damper door mounting and actuation means of the instant invention.

FIG. 4 is a partial sectional view of the display door mounts and the cable system which interconnects with and actuates the damper door.

FIG. 5 is a sectional side elevational view of the refrigerator display case of FIG. 1.

FIG. 6 is a sectional top elevation view of the refrigerator display case of FIG. 1 showing a typical location of the telescopic hole closing means associated with the cold air duct.

FIG. 7 is a partial perspective view of the cold air distribution duct and associated telescopic air distribution and hole closing means.

DETAILED DESCRIPTION OF THE INVENTION Referring initially to FIG. 1, a refrigerator display case 10 is disclosed comprising a longitudinally extending cabinet 12 having a cooling coil and blower portion 14 on one end and food supporting shelves l6 positioned in the display portion of the cabinet. Sliding glass doors l8 and 20 are shown mounted on one side of the cabinet to provide access to the food on the display shelves 16, but it will be understood that if desired, doors may be provided on both sides of the cabinet 12 with suitable modifications being made to the display shelves to allow cool air to circulate directly therethrough.

Referring additionally to FIG. 2, cabinet 12 is shown to include a conventional insulated shell comprising an outer skin 22 of sheet metal, plastic, wood or'the like, an inner insulating layer 24 of conventional insulation material, and an inner metal or plastic skin 26. A mirror 28 is shown mounted conventionally in the upper rear portion of the display case to highlight the food displayed on shelves l6. Shelves 16 are mounted on conventional longitudinal support brackets 30 running between the ends of the display cabinet 12. As shown in FIG. 2, lower shelf 16 is spaced approximately one inch from the rear wall of the cabinet to allow cool air to circulate therethrough and reduce the amount of air flowing around the front of the shelf and against the glass doors, while the upper shelf is spaced approximately one half inch from the rear wall for like reason.

A cold air distribution duct 32 having a top surface 34 which includes a plurality of air holes 36 supported on side walls 38 is shown mounted on the bottom of the cabinet 12. Duct 32 is open at one end to the cooling coil and blower portion 14 of cabinet 12 and directs cool air from the coils along the bottom of the cabinet from whence it passes up through holes 36, circulates around shelves 16 as shown generally by dashed arrows 40 and is drawn into warm air return duct 42 positioned along the top surface of the cabinet above false ceiling.

44. As will be described more completely hereafter, channel 46 is positioned within cold air distribution duct 32 to close selected holes 36 in plate 34 to control the passage of cold air into the display area of cabinet 12. Fluorescent lighting fixtures 48 are shown mounted along the top surface of the cabinet in a conventional manner.

Referring now to FIGS. 3, 4 and the mountings of sliding doors l8 and are shown to comprise hangers 50 and 52 mounted on the top surfaces of the doors and including rollers 54 which run in cooperating tracks 56 mounted on the inside top surface of cabinet 12. Hangers 50 and 52 include cables 58 and 60 connected thereto at points 62 and 64 respectively. Cable 58 runs laterally from connection 62 over sheave 66 and supports a vertically movable counterbalance weight 68 on its end. Referring particularly to FIG. 5, cable 60 runs laterally from connection point 64 about a rotatable sheave 70 mounted on the end of the cabinet distal from cooling coil chamber portion 14, and then laterally along the tops of doors l8 and 20 over sheave 71 mounted coaxially with sheave 66, and about sheave 72 to support vertically movable counterbalance weight 74. Turnbuckles 76 are shown mounted along the cables to allow the lengths of the cables to be adjusted so that the counterbalance weights may be positioned to cause the doors 18 and 20 to automatically and completely close in response to the descent of the counterbalance weights.

Damper door 78 extends completely across warm air return duct 42 and is edge mounted on rotatable shaft 80 on which sheaves 66 and 71 over which the cables 58 and 60 run are also mounted. It will be understood that as either of the doors 18 or 20 is slid open, associated cable 58 or 60 moves over sheave 66 or 71 respectively causing the sheave and shaft 80 on which it is mounted to rotate to pivot damper door 78 upwardly against door stop 82 (FIG. 4) in the direction of dashed arrow 84 to close warm air return duct 42. Once door 78 has pivoted against the stop 82, movement of the damper door ceases while the cable 58 or 60 may continue to slide through its associated sheave 66 or 71 until the cabinet door is opened the desired amount. When the food has been removed from the display shelves and the door handle released, the associated counterbalance weight 68 or 74 moves downwardly causing the attached cable to rotate damper door 78 in the counterclockwise direction in FIG. 4 against stop 86 whereupon the movement of the damper door ceases while the cable continues to slide through the associated sheave 66 or 71. From the above, it will be understood that the connection of the warm air duct 42 with the cooling coil portion 14 of cabinet 12 is closed automatically whenever door 18 or 20 is opened, and that-the duct 42 is automatically opened to chamber 14 whenever the doors l8 and 20 are closed. In this manner, warm air is prevented from being drawn into the cooling display cabinet directly by the fan or blower associated with the cooling'coil and the cool temperature of the cabinet is more easily maintained even with repeated door openings.

Cooling coil and blower 88 may be of any conventional type available on the market, suitably sized with respect to the volume of the display cabinet to be cooled and the anticipated number of door openings, and has thus been illustrated in the drawings merely by the box labeled coil.

Referring additionally to FIGS. 6 and 7, cold air duct 32 is shown to comprise an inverted U-shaped metal duct having side walls 38 and a top plate 34 with a plurality of holes 36 extending therethrough. Cold air from the cooling coil portion of the cabinet 14 is blown into the adjacent end of duct 32 and travels therethrough toward end 90 of the duct at which point the cold air moves out of the duct upwardly into the display cabinet. While some of the cold air runs completely through duct 32 and out end 90, it will be understood that much of the air passes upwardly through holes 36 as it travels along duct 32. As illustrated, holes 36 are equally spaced along top plate 34 and thus it will be understood that, absent channel member 46 discussed briefly heretofore, most of the cold air would pass out of duct 32 through the holes nearest the coil portion,l4 of the cabinet 12 while the holes near end 90 of duct 32 would have a relatively small amount of cold air passing therethrough. This unbalanced cold air distribution might well result in fogging of the windows of door 20 or in the failure of the cabinet to maintain an equal temperature throughout or a desired cool temperature at the end of the cabinet aware from the coil 88.

As illustrated, channel member 46 comprises three inverted U-shaped sections 92, 94 and 96 telescopically slidable one within the other and having solid top surface panels which effectively block the holes 36 beneath which they are positioned to prevent air from passing upwardly therethrough into the display cabinet. When the three channels are telescoped outwardly as shown in FIG. 7, it will be understood that at least some of the air passing into channel member 92 is lead directly out of the end of channel portion 96 at end 90 of air duct 32, while other portions of the air escape at intermediate distances therealong at openings 98 and 100. Channel member 46 effectively reduces the amount of air passing through the holes 36 at the end of duct 32 adjacent the cooling coil by closing the holes at that end of duct 32. At the same time, cold air is channeled directly toward end 90 of duct 32 thereby allowing equalization of cool air flow into the cabinet. It will be understood that channel 46 may be moved laterally within duct 32 to close any selected configuration of holes and that the telescoping members may be lengthened or shortened to additionally regulate the passage of air through holes 36 thus allowing a near unlimited variation in air distribution capabilities.

Referring again to FIG. 2, an alternate form of channel 46 is shown wherein panel 102 is mounted for longitudinal telescopically sliding movement on the bottom portion of panel 104 which is in turn mounted for longitudinally telescoping movement on the bottom surface of panel 106. This arrangement functions in substantially the same manner as the channel member of FIG. 7 described above although the outwardly telescoping plates 102 and 104 do not have vertical side supports and thus the amount of air flowing directly to the end 90 of duct 32 is somewhat reduced in favor of additional air flow through the holes 36.

lt will be understood that as is common with food display cases, the entire cool air duct structure as well as the channel structure 46 may be easily removed from the cabinet 12 for cleaning, as may shelves 16.

The invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.

What is claimed is:

1. In a refrigerator display case of the type including a cabinet, a cooling coil and blower end mounted within said cabinet, vertically spaced food supporting shelves mounted within said cabinet and laterally sliding doors on said cabinet providing access to the food on said shelves, the improvement comprising a cool air circulation system including:

duct means directing cool air from said end mounted cooling coil and blower along the bottom of said cabinet, said duct means including a top plate means having a plurality of holes therein through which said cool air moves upwardly into said cabinet;

longitudinal channel means positioned within said duct means and beneath said top plate means to selectively close said holes therein to control the distribution of cool air to said cabinet; and

damper means controlling the return flow of air to said end mounted cooling coil, said damper means being mechanically linked to said sliding doors and closable in response to the opening of said doors.

2. The refrigerator display case of claim 1, wherein said longitudinal channel means is configured to close a greater number of holes on the end of said cabinet adjacent said cooling coil than on said distal end.

3. The refrigerator display case of claim 1 wherein said longitudinal channel means comprises a plurality of panels telescoping longitudinally away from the cooling coil and blower end of said cabinet, said telescoping panels furthermost from said cooling coil having smaller hole closing surface area than said panels adjacent thereto.

4. The refrigerator display case of claim 1 including duct means mounted adjacent the top portion of said cabinet and directing the flow of warm air to said cool-' ing coil, said duct means including said damper means mounted at the cooling coil end thereof.

5. The refrigerator display case of claim 4 wherein said damper means is fixedly mounted on a rotatable shaft extending transverse said warm air return duct means, said shaft including a pair of sheaves mounted coaxially at one end thereof;

a pair of cords connected at one end to each of said sliding doors and having weight means mounted on their opposite ends, each of said cords running over one of said sheaves;

said cords bearing on said sheaves to rotate said damper to close said warm air return duct when said doors are opened, and said cords bearing on said sheaves to rotate said damper to open said warm air duct when said weights automatically close said doors.

6. In a refrigerator display case of the type including a cabinet, a cooling coil and blower end mounted within said cabinet, vertically spaced food supporting shelves mounted within said cabinet and laterally sliding doors on said cabinet providing access to the food on said shelves, the improvement comprising a cool air circulation system including:

duct means directing cool air from said end mounted cooling coil and blower along the bottom of said cabinet, said duct means including a top plate means having a plurality of holes therein through which said cool air moves upwardly into said cabinet;

longitudinal channel means positioned within said duct means and beneath said top plate means to selectively close said holes therein to control the distribution of cool air to said cabinet; and

said longitudinal channel means configured to close a greater number of holes on the end of said cabinet adjacent said cooling coil than on said distal end.

7. The refrigerator display case of claim 6 wherein said longitudinal channel means comprises a plurality of panels telescoping longitudinally away from the cooling coil and blower end of said cabinet, said telescoping panels furthermost from said cooling coil having smaller hole closing surface area than said panels adjacent thereto. 

1. In a refrigerator display case of the type including a cabinet, a cooling coil and blower end mounted within said cabinet, vertically spaced food supporting shelves mounted within said cabinet and laterally sliding doors on said cabinet providing access to the food on said shelves, the improvement comprising a cool air circulation system including: duct means directing cool air from said end mounted cooling coil and blower along the bottom of said cabiNet, said duct means including a top plate means having a plurality of holes therein through which said cool air moves upwardly into said cabinet; longitudinal channel means positioned within said duct means and beneath said top plate means to selectively close said holes therein to control the distribution of cool air to said cabinet; and damper means controlling the return flow of air to said end mounted cooling coil, said damper means being mechanically linked to said sliding doors and closable in response to the opening of said doors.
 2. The refrigerator display case of claim 1, wherein said longitudinal channel means is configured to close a greater number of holes on the end of said cabinet adjacent said cooling coil than on said distal end.
 3. The refrigerator display case of claim 1 wherein said longitudinal channel means comprises a plurality of panels telescoping longitudinally away from the cooling coil and blower end of said cabinet, said telescoping panels furthermost from said cooling coil having smaller hole closing surface area than said panels adjacent thereto.
 4. The refrigerator display case of claim 1 including duct means mounted adjacent the top portion of said cabinet and directing the flow of warm air to said cooling coil, said duct means including said damper means mounted at the cooling coil end thereof.
 5. The refrigerator display case of claim 4 wherein said damper means is fixedly mounted on a rotatable shaft extending transverse said warm air return duct means, said shaft including a pair of sheaves mounted coaxially at one end thereof; a pair of cords connected at one end to each of said sliding doors and having weight means mounted on their opposite ends, each of said cords running over one of said sheaves; said cords bearing on said sheaves to rotate said damper to close said warm air return duct when said doors are opened, and said cords bearing on said sheaves to rotate said damper to open said warm air duct when said weights automatically close said doors.
 6. In a refrigerator display case of the type including a cabinet, a cooling coil and blower end mounted within said cabinet, vertically spaced food supporting shelves mounted within said cabinet and laterally sliding doors on said cabinet providing access to the food on said shelves, the improvement comprising a cool air circulation system including: duct means directing cool air from said end mounted cooling coil and blower along the bottom of said cabinet, said duct means including a top plate means having a plurality of holes therein through which said cool air moves upwardly into said cabinet; longitudinal channel means positioned within said duct means and beneath said top plate means to selectively close said holes therein to control the distribution of cool air to said cabinet; and said longitudinal channel means configured to close a greater number of holes on the end of said cabinet adjacent said cooling coil than on said distal end.
 7. The refrigerator display case of claim 6 wherein said longitudinal channel means comprises a plurality of panels telescoping longitudinally away from the cooling coil and blower end of said cabinet, said telescoping panels furthermost from said cooling coil having smaller hole closing surface area than said panels adjacent thereto. 